TY - CHAP
T1 - Light absorption by photoplankton and the vertical light attenuation
T2 - ecological and physiological significance
AU - Schanz, F.
AU - Senn, P.
AU - Dubinsky, Z.
PY - 1997
Y1 - 1997
N2 - The chlorophyll a specific light attenuation coefficient kc, (in m2mg-1 chl a), is an apparent optical property of the underwater light field, resulting from the interaction between sunlight and the phytoplankton suspended in natural waters. The determination of kc is carried out under the natural light conditions of a water body, whereas the specific light absorption coefficient of chlorophyll a, aph (in m2mg-1 chl a), is an inherent optical property of the phytoplankton. That parameter, aph, is determined using a laboratory spectrophotometer. Both kc and aph are necessary to calculate the quantum requirement of phytoplankton photosynthesis from α, the linear part of the photosynthesis versus irradiation curve. The spectral distribution of kc(λ) and aph(λ) contains information about the species composition of the phytoplankton community. Different ways to determine kc or aph are presented. It is relatively easy to evaluate k-c(= k-c(PAR)), the wavelength-average over the photosynthetically available radiation (PAR) range, assumed to be from 400 nm to 700 nm. Alternatively, in the literature such values were also calculated from the much more difficult to measure kc(λ)-spectrum, and the spectral distribution of underwater irradiance, E(λ). The values of kc and aph are influenced by technical, physical and biological factors: the method of chlorophyll determination, the filter loading, the light properties of the water bodies, the species composition of the phytoplankton community, including cell geometry and size, the ultrastructure of chloroplasts and the physiological status of the cells, resulting from senescence, nutrient limitation or photoacclimation.
AB - The chlorophyll a specific light attenuation coefficient kc, (in m2mg-1 chl a), is an apparent optical property of the underwater light field, resulting from the interaction between sunlight and the phytoplankton suspended in natural waters. The determination of kc is carried out under the natural light conditions of a water body, whereas the specific light absorption coefficient of chlorophyll a, aph (in m2mg-1 chl a), is an inherent optical property of the phytoplankton. That parameter, aph, is determined using a laboratory spectrophotometer. Both kc and aph are necessary to calculate the quantum requirement of phytoplankton photosynthesis from α, the linear part of the photosynthesis versus irradiation curve. The spectral distribution of kc(λ) and aph(λ) contains information about the species composition of the phytoplankton community. Different ways to determine kc or aph are presented. It is relatively easy to evaluate k-c(= k-c(PAR)), the wavelength-average over the photosynthetically available radiation (PAR) range, assumed to be from 400 nm to 700 nm. Alternatively, in the literature such values were also calculated from the much more difficult to measure kc(λ)-spectrum, and the spectral distribution of underwater irradiance, E(λ). The values of kc and aph are influenced by technical, physical and biological factors: the method of chlorophyll determination, the filter loading, the light properties of the water bodies, the species composition of the phytoplankton community, including cell geometry and size, the ultrastructure of chloroplasts and the physiological status of the cells, resulting from senescence, nutrient limitation or photoacclimation.
UR - http://www.scopus.com/inward/record.url?scp=0031394349&partnerID=8YFLogxK
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AN - SCOPUS:0031394349
T3 - Oceanography and Marine Biology: an annual review. Vol 35
SP - 71
EP - 95
BT - Oceanography and Marine Biology
A2 - Ansell, A.D.
A2 - Gibson, R.N.
A2 - Barnes, M.
PB - UCL Press
ER -